Pneumatic cutting tool



April 3,1956 5. F. TOFFLEMIRE 2,740,406

PNEUMATIC CUTTING TOOL Filed July 26, 1954 2 Sheets-Sheet l L o L U I 1INVENTOR BENJAMIN F-TOFFLEM1RE y ATTORNEYS T 5 +6 12 F 16 23 P N l 1 I)25 April 3, 1956 B. F. TOFFLEMIRE 2,740,406

PNEUMATIC CUTTING TOOL Filed July 26, 1954 2 Sheets-Sheet 2 AT TORNEYSUnited States Patent PNEUMATIC CUTTING TOOL Benjamin F. Tofliemire;Lafayette, Calif. Application-July 26; 1954, Serial No, 445523 Claims.(Cl. 128-310) in thoseinaccessible and difiicult-to-reachareas found inimpaction-work in eXodontia and; bone-surgery, as well astheconstrictedareasin industry. Heretofore, hammer-andchisel work' in theseconstricted areas-made many of 'these operations not onlyverydifii'cultto perform; but"'the:'use of the chiselwasinefficienfandfim efiectivez- 'Ifhe lightness of the instrument'permits'the surgeon'to continue'his intricate work without tiringorbeingplaced under a nervous strain; Alsothe 'compactncss 'ofth'einstrument reduces the apprehensiona nd nervousness-of the patient incase the operation is-do'ne' under a local anesthetic.

Another novel feature lies in the adaptation of carbon dioxide gasunderpressure-for the operationof the device instead' of by compressedair or any other'compressed gas. Carbon dioxide can be storedin'pprtablecontainers and used for operating the tool 'when' needed. This not onlyobviates the necessity of having=an-aircompressor available;but alsoeliminates the use-ofnonsterile; water-vaponladen air in the operativenew where the tool is being used. Theelimination"of the watervapordzidenair, moreover; further'protectsmnw of the accessory equipment, such'as-cutters;- gouges, elevators, etc: from rust' andicorrosion. v

A novel exhaust control mechanism-of this instrument,

diverts and conducts the airor gas used 'to-operate th'e device,away--'from th'eoperating-fielm thereby -ahsolutely preventingany'possible contamination=- of"the operative field! This featureisveryessentialito a su'r-geona- The instrument 'is-made throughout of"stainless steel and so designed as to permit sterilization of theentire instrument. The corrosion resistantproperties of the-devieeassures ithaving ta long life and freedorn from "rust-and othercorrosioninduced contaminants.

A toot-pedal control of the instrument= permits the operator toconcentrate on precision guidance of the instrument' without thedistracting; lossof control and Wavei'ing -oc'casioned-by the--grip=changenecessitated by a hand-operated control valve.

The-Icomplete portabili'ty"of the instrument and the compressedcar-bondioxide gas; permits the surgeon-to carry the equipment with himon emergency calls'gor OPEIHtEilHlthB home :orein ssmall'er rhospitals:not e quipped safe compress'or: service: Likewise, .the trouble.-shooter -"ine.industries; may CHYIYFthQi equipmentr; to sthe scene@ff-the troubles-and .permitr-him: to: reachethosercon- 2 strictedareas'with an eflicient; rapid, andlfully controlled device.-

Various cutting instruments such as trimmers, gouges, chisels, rougeurs,and planes, are allreadily interchangeable and*are:so-designed as to beinserted orremoved with the minimum time; etfort and confusion.

Otherobjects and advantageswill appearin the following specification,andthe novelfeatures'of the device will beparticularly pointed outin theappendedclaimsr,

My invention is illustrated in the accompanying drawingsforming a part'of this application; in which:

Figure- 1-is"a-view ofthe tool shown operatively connectedto a tank ofcompressed gas;

Figure 2 is an enlarged-elevational'view of the, tool;

Figure 3 is an enlarged longitudinal section taken along thdlihelIP-IIIof Figure 1 and'illustrates the pneumatically operated parts in intakeposition;

Figure 4'isalongitudinal "section taken along, the lineIV-'-IVbfFigure-3 andshows the pneumaticallyoperated parts'in exhaustposition;

Figure 5' is a longitudinal section taken through thecylinderand'sh'ows" the piston in elevation and in; the same position*as in Figure 3;

Figure is a transverse section taken along the line VI -V1 of-Figure 5and illustrates the cylinder;

Figure 7 is aplan view of a disc that closes-the lower endlzofthecylinder; and the view istaken'wh'enlookin'g in the direction ofthearrows VIl,-VII of'Fig'ureS; and

Figure '8 is"an elevationalview of"the,inlet tube and associate parts.-

while I have shown onlythe preferred 'forrrr'of 'my invention; itshoulwbe understoodfthat various changes ormrodifieat-ionsmay-'bemadewithinithescope of the appended claims without departing fromthe, spirit. and scope of the-invention. V

In carrying out myinvention I *will'gdescrihe the structural *p arts as=shownrin Figures to 8;,inclusiv'e; and then will set forth how the tool;can the connecteditoza' -tankof*compress ed"g as, such-as carbon:dioxide." Itis bestfiist td refer" to "Figure 5 "wherein I showthecylinder as -having-arcylindrical bore lin: which a piston 'Bisreciprocably mounted. Itwill be noted that the ;upper thanthe lowerportion- 11) of'th'e same here 'and'that the cylinder, is-providedwithan annular groove 2" at; the juncture of thecylindricalbore' portions1:: and 111; [The piston h'as; an upper reducedportionfi 1 which, is ofthe same-diameter asthe' cylindrical bore portion l'a 'an d has a-ldwer*larger portion' 4of a diameter-that is the same as the diameter-of' the -'lower'cylindric'a1 portion'db. Then-piston B is freeto*slidewithin-the b'ore lof the cylinder-mvi-thin certainzlimits. A' Ishoulder5t-is formed on: the pis'tomrBi at.:the sjunctureyof'i thei portioni3!.with therpor ionA-w I provide-the pistonsB with anwaxialwairpassager6 that-\extendsfrom athe; bottom- 7 of the-pistont-upwardlytosaapoint inatheereducedspprtion S -Where-Ythe top of the.air,..ducbeommunicates with. at diametrically extend ing air passage,.8,-whose ends terminate: at theaouter surface of the cylindricalportiondtWhen the pistonsB is. in, intake position, the air passage 8 will-havefit's, ends both'intcommunication with the annular air, passage 2.ThecyliiiderA has'a'bl'eed opening 9'near its top that communicates withthe upper boreportion 1a, seeFi'gure 5} and the -cylinder also hasdiametrically; opposed exhau'sh ports 10, see Figure-4 thatareplacedinthe lower bore porti'on 1b of the cylinders and are-uncovered when thepistoinmovesmpwardly in th'eeylinder:

- Before :describingrthetoperationzoff th'e'piston, it is best.firstrtorset:forthzthatnthe;uppersend 1 .ofifthe cylinder rsceivesiztheinnenendiofsaaguide sleeve-:6, ,see :Eig'nrert;

Patented Apr. 3, 1956 the exhaust ports for This guide sleeve has anoutwardly-extending annular flange 11 that rests against the top of thecylinder A, as clearly shown in Figure 5. A retaining flange nut 12 isthreaded upon a threaded outer portion 13 of the upper end of thecylinder A and the nut acts as a fastening means for holding the guidesleeve C to the cylinder A. Within the guide sleeve C, I reciprocablymount a plunger D, see Figure 3, and this plunger carries a pin 14 thatextends transversely therethrough and has its ends slidably received inguide slots 15 that are provided in the guide sleeve C and are disposeddiametrically opposite one another. The pin 14 performs the dualfunction of preventing rotation of the plunger D, while permitting alimited longitudinal movement thereof. The piston B on its outwardmovement will strike the plunger D and move it until the ends of the pin14 reach the ends of the guide slots 15, whereupon further movement inthe same direction is prevented.

A cutting implement such as a chisel E has its shank 16 provided with anotch 17 and the shank is also provided with a flattened portion 18 inline with the notch and disposed at the end of the shank. A leaf springF is pivoted to the plunger D by means of a screw 19 and the inner endof this screw is positioned adjacent to the flat-' tened portion 18 onthe shank 16 of the chisel E to prevent rotation of the chisel withrespect to the plunger. The free end of the leaf spring F carries adetent 20 and this detent is slidably received in an opening 21 providedin the plunger D and is removably received in the notch 17 of the chiselshank 16 for holding it in place. The plunger D has a socket 22 forremovably receiving the chisel shank 16. V

The work on which the chisel operates is indicated generally at G inFigure 3, and this may be a bone if the chisel is used for surgerypurposes, or it may be a piece of wood or other material. When thepointed end 23 of the chisel is directed against the work G so as toshave 0d a portion as indicated at 24 in Figure 3, the forcing of thetool against the work will tend to move the plunger D inwardly in theguide sleeve C until the outward annular flange 25 on the plunger Dstrikes the outer end of the guide sleeve. This movement will cause ure3. The plunger may be moved to close the inlet V the inner end of theplunger to move inwardly from the inner end of the guide sleeve so thatthe plunger will be in a position to be struck by the advancing piston Bon its power stroke. The piston in its reciprocations will thereforedrive the plunger D and the chisel E outwardly, while the force of thechisel on the work will drive the plunger inwardly as soon as the pistonB has delivered its blow and starts on its return movement within thecylinder. The pin 14 holds the plunger D from flying clear of thecylinder A when the piston B strikes it.

I will now describe the means for conveying a compressed gas to thecylinder A and for conveying the spent or exhaust gas to the rear of theinstrument so that this gas will not contaminate the operative area whenthe device is used for surgical purposes. Referring to Figure 1, it willbe seen that I make use of a portable tank indicated generally at H andthis tank may contain any kind of compressed gas or air desired. It isbest to use carbon dioxide if the instrument is to be used for surgicalpurposes because this gas cannot be ignited by a spark.

The tank H is provided with a main valve 26 and this controls the flowof the compressed gas to a pressure regulator indicated generally at I.A control handle 27 is mounted on the pressure regulator I and deliversthe compressed gas at the proper pressure to a flexible hose 28. Thecontrol handle 27 may be adjusted so that the gas will be delivered tothe instrument at a desired pres sure and a pressure gauge K willindicate this pressure. A shutoff valve L is placed in the flexible line28 and this valve is opened when the instrument is to be used. Ifdesired, a foot-control valve indicated generally at M is placed in theflexible line 28 and this will shut off the flow of gas to theinstrument until a foot pedal 29 is depressed for opening thefoot-control valve.

Now referring to Figure 3, it will be seen that the flexible hose 28that carries the compressed gas has its free end attached to a conicalsurface 30 of an inlet tube N. A nut 31 clamps the outer end of the hoseto the control end 3! and makes a gas-tight seal therewith. Figure8-shows the inlet tube provided with a hand control cutoir" valve P.Figure 3 shows the valve P provided with a plunger 32 and this plungerhas a passage 32 that is aligned with the bore 33 provided in the inlettube N when the plunger is in the position shown in Figpassage 33.

The inlet tube has its upper end permanently secured to a cup-shapedpart Q, see Figure 8. The outer surface of this cup-shaped part Q isprovided with a plurality of longitudinally extending and spaced-apartgrooves 34. Figure 8 shows the exhaust ports 10 registering with certainof these grooves-34. Figure 4 illustrates how the upper end of thecup-shaped member Q is internally threaded at 35, andthese threadsreceive the threads 36 on the outer surface of the cylinder A, seeFigure 5. The exhaust ports 10 in the cup Q register with the exhaustports 10 in the cylinder A.

The lower end of the cylinder A is closed by means of a disc R and thisdisc is shown in Figures 5 and 7. The disc has pins 37 that are receivedin recesses 38 provided in the lower end of the cylinder A. When thedisc R is in place to close the lower end of the cylinder, it will beseen from Figures 5 and 7 that the inlet ports 39 in the disc willregister with inlet passages 40 that extend longitudinally in thecylinder A from a lower end thereof up to the annular grooves 2 so as tocommunicate therewith. An annular shoulder 41 is provided within theinterior and at the bottom of the cup-shaped portion Q, seeFigure 4, andthis shoulder spaces the disc R above the bottom of the cup so that thecompressed gas can flow from the passage 33 of the inlet tube N, intothe passages 40, see Figure 3, and then into the annular groove 2.

When the piston B is in its intake position as shown in Figure 3, thecompressed gas will flow from the annular groove 2 and enter both endsof the transverse passage 8 in the piston B. The compressed gas willthen flow downwardly through the passage 6 from the passage 8,

and will enter the lower compartment A1 of the cylinder.

It will be seen that the compressed gas will force the piston B upwardlyon a power stroke to strike the inner end of the plunger D and cause thechisel to cut the work G as indicated at 24 in Figure 3.

When the piston B nears the top of its power stroke, as shown in Figure4, it will uncover the exhaust ports 10 and permit the trappedcompressed gas to pass through these ports and enter the grooves 34 andflow downwardly in these grooves. An outer sheath S covers the tops ofthe grooves 34 so as to form them into passages. Figure 4 shows thesheath as telescoping over the cylinder A as well as over the cup-shapedmember Q and as having a flange 42 at its top that is received in anannular groove 43 formedat the top of the cylinder A. The hexagonal nut12 holds the flange 42 in the groove 43.

An outlet tubular member T, see Figures 3 and 4, has one end secured tothe outer sheath S by the screw threads 44 and this tubular member isspaced from the inlet tube N so as to provide an annular exhaustpassageway 45 that will lead the exhaust gases to the rear end of theinstrument as shown in Figure 4, which is at a remote point from thechisel E. A

From the foregoing description of the various parts of the device, theoperation thereof may be readily under.-

stood.

The tool maybe held in the hand in much the same manner as a fountainpen." The thumb and forefinger can grip the smooth cylindrical portion46, see Figure l, of the outer sheath S, and the knurled outer surface'41- of the outlet tubular member T will rest on the portion of the samehand that connects the thumb with the index finger. The operator cansupport his hand when using the tool by resting the tops of the fingersthat do not contact with the instrument, on the work being acted uponand he can guide the pointed end 23 of the chisel E against the workwith a high degree of skill. Delicate control is possible when using thetool in this manner.

Both the shutolf valve L and the hand control valve P are moved intoopen position. The foot pedal 29 may be used for controlling the footvalve M. It is not necessary that both valves M and P be used. Thecompressed gas will flow through the inlet passage 33 of the inlet tubeN when the valve M is opened and then will flow through the openings 39in the disc R to enter the longitudinal passages 40 in the cylinder A.The gas will then flow into the annular groove 2 and thence into thetransverse passage 8, the longitudinal passage 6, in the piston B, andwill enter the lower chamber A1 of the cylinder. The piston will bemoved on its power stroke by the gas trapped in the lower chamber A1 andforcing against the bottom of the piston to move it upwardly. Anytrapped gas in the cylinder bore 1 which is above the piston will escapethrough the bleed outlet 9 and will enter the space between the sheath Sand the outer surface of the cylinder A. From here the trapped gas canflow along the grooves 34 and out through the exhaust passage 45.

The upward movement of the piston B from Figure 3 to Figure 4, on itspower stroke, will cause the piston to strike the plunger D and move ittogether with the chisel against the work G. When the piston is in itsuppermost position, the inlet bore 8 in the piston, will be out ofregistration with the inlet groove 2 and therefore no more compressedgas can enter the bores 8 and 6. The upward movement of the piston willuncover the exhaust ports 10 and permit the compressed gas in thecylindrical compartment A1 to escape therethrough and to flow along thegrooves 34, and out through the passage 45.

The piston is returned to its starting position by the compressed gas inthe groove 2 bearing against the shoulder 5 on the piston, and by thefact that the piston upon striking the plunger D will rebound and starton its return movement. The compartment A1 has been relieved of its gaspressure and therefore the piston will move from the position shown inFigure 4 into that shown in Figures 3 and 5. The end of the returnmovement of the piston will be cushioned because the gas in thecompartrnent A1 will be trapped as soon as the piston closes the exhaustports 10. There will be no metallic sound from the piston as it returnsin its movement and is ready to start on its next power stroke.

There will be no cushioning effect of the piston on its power strokewhen striking the plunger D because any trapped gas in the upper part ofthe cylinder will escape through the bleed hole 9. As soon as the pistonreturns in its movement from the position shown in Figure 4 into thatshown in Figure 3, the plunger D will also return in its movementbecause the chisel E is continually held against the work during thecutting operation. The pin 14 limits the outward movement of the chiselE as well as holds the chisel from rotating in the guide sleeve C.

The operator can control the instrument for delicate bone surgery andcan stop and start the flow of compressed gas to the instrument by usingeither the foot valve M or the hand valve P.

Dry carbon dioxide is a relatively inert and a very stable compound. Thegas inhibits the growth of or actually destroys bacteria. Thisgermicidal action increases in line with the number of volumes ofcarbonation used. Therefore, using carbon dioxide under pressure tooperate the device for surgical purposes will give an additional safetyfactor for the success of the operation. The inert gas will prevent anypossibility of an explosion and it has fire extinguishing properties.

I claim:

1. A pneumatically operated tool comprising: a cylinder; a pistonreciprocably mounted therein; a plunger placed at one end of thecylinder and adapted to be contacted by the piston; a guide for theplunger and secured to the cylinder; a cutting implement carried by theplunger; means for delivering gas under pressure to the cylinder forreciprocating the piston; said cylinder having exhaust ports uncoveredby the piston when the latter moves in one direction; and a sheathenclosing the cylinder and having passageways communicating with theexhaust ports and extending beyond the end of the cylinder opposite tothe plunger for delivering the exhaust gases at a point remote from thecutting implement.

2. A pneumatically operated tool comprising: a cylinder; a pistonreciprocably mounted therein; a plunger placed at one end of thecylinder and adapted to be contacted by the piston; a guide for theplunger and secured to the cylinder; a cutting implement carried by theplunger; an inlet tube axially aligned with and operatively connected tothe cylinder and adapted to deliver com pressed gas to the cylinder forreciprocating the piston; said cylinder having exhaust ports uncoveredby the piston when the latter moves in one direction; and a sheathenclosing the cylinder and a portion of the inlet tube and forming anexhaust passage that communicates with the exhaust ports and extends tothe end of the sheath enclosing the inlet tube.

3. A pneumatically operated tool as defined in claim 2, in combinationwith: a flexible hose connected to the inlet tube; a portable tankcontaining dry, germicidal, non-explosive carbon dioxide gas underpressure; said hose communicating with the tank; and a valve arrangedfor controlling flow of gas from the tank to the inlet tube.

4. in a pneumatically operated tool: a cylinder; a piston reciprocablymounted in the cylinder; at plunger mounted in one end of the cylinderand adapted to be struck by the piston when the latter moves in onedirection; means for limiting the outward movement of the plunger; acutting instrument removably carried by the plunger; an inlet tubeextending from the opposite end of the cylinder to that of the plungerand being axially aligned with the cylinder; means for delivering gasfrom the tube to the interior of the cylinder for reciprocating thepiston; said cylinder having a bleed opening disposed adjacent to theplunger and having exhaust ports placed nearer the opposite end of thecylinder; and a sheath enclosing the cylinder and a portion of the inlettube and constituting a passage for any gases escaping from the bleedopening or from the exhaust ports.

5. A pneumatically operated tool comprising a cylinder; a pistonreciprocably mounted therein; an instrument-carrying plunger disposed atone end of the cylinder, the plunger being struck by the piston eachtime the latter is reciprocated; an inlet tube having a cupshaped memberenclosing the end of the cylinder disposed opposite to the plunger; saidcylinder having intake passages placing the inlet tube in communicationwith the interior of the cylinder; said cylinder and cupshaped memberhaving exhaust ports extending therethrough; the outer cylindricalsurface of the cup-shaped member having longitudinally extending groovesthat register with the exhaust ports; and a sheath enclosing thecylinder, the cup-shaped member and the greater portion of the inlettube; said sheath being spaced from the inlet tube and constituting apassage for the exhaust gases from the grooves to the end of the sheaththat surrounds the inlet tube; this end of the sheath opening to theatmosphere for permitting the escape of the exhaust gases. at a pointwhich is remote from the instrument carried by the plunger.

Germany June 10, 1926

